/* * drivers/cpufreq/cpufreq_ondemand.c * * Copyright (C) 2001 Russell King * (C) 2003 Venkatesh Pallipadi . * Jun Nakajima * (c) 2013 The Linux Foundation. All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * dbs is used in this file as a shortform for demandbased switching * It helps to keep variable names smaller, simpler */ #define DEF_FREQUENCY_DOWN_DIFFERENTIAL (10) #define DEF_FREQUENCY_UP_THRESHOLD (80) #define DEF_SAMPLING_DOWN_FACTOR (1) #define MAX_SAMPLING_DOWN_FACTOR (100000) #define MICRO_FREQUENCY_DOWN_DIFFERENTIAL (3) #define MICRO_FREQUENCY_UP_THRESHOLD (95) #define MICRO_FREQUENCY_MIN_SAMPLE_RATE (10000) #define MIN_FREQUENCY_UP_THRESHOLD (11) #define MAX_FREQUENCY_UP_THRESHOLD (100) #define MIN_FREQUENCY_DOWN_DIFFERENTIAL (1) /* * The polling frequency of this governor depends on the capability of * the processor. Default polling frequency is 1000 times the transition * latency of the processor. The governor will work on any processor with * transition latency <= 10mS, using appropriate sampling * rate. * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL) * this governor will not work. * All times here are in uS. */ #define MIN_SAMPLING_RATE_RATIO (2) static unsigned int min_sampling_rate; #define LATENCY_MULTIPLIER (1000) #define MIN_LATENCY_MULTIPLIER (100) #define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000) #define POWERSAVE_BIAS_MAXLEVEL (1000) #define POWERSAVE_BIAS_MINLEVEL (-1000) static void do_dbs_timer(struct work_struct *work); static int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event); #ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND static #endif struct cpufreq_governor cpufreq_gov_ondemand = { .name = "ondemand", .governor = cpufreq_governor_dbs, .max_transition_latency = TRANSITION_LATENCY_LIMIT, .owner = THIS_MODULE, }; /* Sampling types */ enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE}; struct cpu_dbs_info_s { cputime64_t prev_cpu_idle; cputime64_t prev_cpu_iowait; cputime64_t prev_cpu_wall; cputime64_t prev_cpu_nice; struct cpufreq_policy *cur_policy; struct delayed_work work; struct cpufreq_frequency_table *freq_table; unsigned int freq_lo; unsigned int freq_lo_jiffies; unsigned int freq_hi_jiffies; unsigned int rate_mult; unsigned int prev_load; unsigned int max_load; int cpu; unsigned int sample_type:1; /* * percpu mutex that serializes governor limit change with * do_dbs_timer invocation. We do not want do_dbs_timer to run * when user is changing the governor or limits. */ struct mutex timer_mutex; }; static DEFINE_PER_CPU(struct cpu_dbs_info_s, od_cpu_dbs_info); static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info); static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info); static unsigned int dbs_enable; /* number of CPUs using this policy */ /* * dbs_mutex protects dbs_enable and dbs_info during start/stop. */ static DEFINE_MUTEX(dbs_mutex); static struct workqueue_struct *dbs_wq; struct dbs_work_struct { struct work_struct work; unsigned int cpu; }; static DEFINE_PER_CPU(struct dbs_work_struct, dbs_refresh_work); struct dbs_sync_work_struct { struct work_struct work; unsigned int src_cpu; unsigned int targ_cpu; }; static DEFINE_PER_CPU(struct dbs_sync_work_struct, dbs_sync_work); static struct dbs_tuners { unsigned int sampling_rate; unsigned int up_threshold; unsigned int up_threshold_multi_core; unsigned int down_differential; unsigned int down_differential_multi_core; unsigned int optimal_freq; unsigned int up_threshold_any_cpu_load; unsigned int sync_freq; unsigned int ignore_nice; unsigned int sampling_down_factor; int powersave_bias; unsigned int io_is_busy; } dbs_tuners_ins = { .up_threshold_multi_core = DEF_FREQUENCY_UP_THRESHOLD, .up_threshold = DEF_FREQUENCY_UP_THRESHOLD, .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR, .down_differential = DEF_FREQUENCY_DOWN_DIFFERENTIAL, .down_differential_multi_core = MICRO_FREQUENCY_DOWN_DIFFERENTIAL, .up_threshold_any_cpu_load = DEF_FREQUENCY_UP_THRESHOLD, .ignore_nice = 0, .powersave_bias = 0, .sync_freq = 0, .optimal_freq = 0, }; static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall) { u64 idle_time; u64 cur_wall_time; u64 busy_time; cur_wall_time = jiffies64_to_cputime64(get_jiffies_64()); busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER]; busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM]; busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ]; busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ]; busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL]; busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE]; idle_time = cur_wall_time - busy_time; if (wall) *wall = jiffies_to_usecs(cur_wall_time); return jiffies_to_usecs(idle_time); } static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) { u64 idle_time = get_cpu_idle_time_us(cpu, NULL); if (idle_time == -1ULL) return get_cpu_idle_time_jiffy(cpu, wall); else idle_time += get_cpu_iowait_time_us(cpu, wall); return idle_time; } static inline cputime64_t get_cpu_iowait_time(unsigned int cpu, cputime64_t *wall) { u64 iowait_time = get_cpu_iowait_time_us(cpu, wall); if (iowait_time == -1ULL) return 0; return iowait_time; } /* * Find right freq to be set now with powersave_bias on. * Returns the freq_hi to be used right now and will set freq_hi_jiffies, * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs. */ static unsigned int powersave_bias_target(struct cpufreq_policy *policy, unsigned int freq_next, unsigned int relation) { unsigned int freq_req, freq_avg; unsigned int freq_hi, freq_lo; unsigned int index = 0; unsigned int jiffies_total, jiffies_hi, jiffies_lo; int freq_reduc; struct cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, policy->cpu); if (!dbs_info->freq_table) { dbs_info->freq_lo = 0; dbs_info->freq_lo_jiffies = 0; return freq_next; } cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next, relation, &index); freq_req = dbs_info->freq_table[index].frequency; freq_reduc = freq_req * dbs_tuners_ins.powersave_bias / 1000; freq_avg = freq_req - freq_reduc; /* Find freq bounds for freq_avg in freq_table */ index = 0; cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg, CPUFREQ_RELATION_H, &index); freq_lo = dbs_info->freq_table[index].frequency; index = 0; cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg, CPUFREQ_RELATION_L, &index); freq_hi = dbs_info->freq_table[index].frequency; /* Find out how long we have to be in hi and lo freqs */ if (freq_hi == freq_lo) { dbs_info->freq_lo = 0; dbs_info->freq_lo_jiffies = 0; return freq_lo; } jiffies_total = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); jiffies_hi = (freq_avg - freq_lo) * jiffies_total; jiffies_hi += ((freq_hi - freq_lo) / 2); jiffies_hi /= (freq_hi - freq_lo); jiffies_lo = jiffies_total - jiffies_hi; dbs_info->freq_lo = freq_lo; dbs_info->freq_lo_jiffies = jiffies_lo; dbs_info->freq_hi_jiffies = jiffies_hi; return freq_hi; } static int ondemand_powersave_bias_setspeed(struct cpufreq_policy *policy, struct cpufreq_policy *altpolicy, int level) { if (level == POWERSAVE_BIAS_MAXLEVEL) { /* maximum powersave; set to lowest frequency */ __cpufreq_driver_target(policy, (altpolicy) ? altpolicy->min : policy->min, CPUFREQ_RELATION_L); return 1; } else if (level == POWERSAVE_BIAS_MINLEVEL) { /* minimum powersave; set to highest frequency */ __cpufreq_driver_target(policy, (altpolicy) ? altpolicy->max : policy->max, CPUFREQ_RELATION_H); return 1; } return 0; } static void ondemand_powersave_bias_init_cpu(int cpu) { struct cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu); dbs_info->freq_table = cpufreq_frequency_get_table(cpu); dbs_info->freq_lo = 0; } static void ondemand_powersave_bias_init(void) { int i; for_each_online_cpu(i) { ondemand_powersave_bias_init_cpu(i); } } /************************** sysfs interface ************************/ static ssize_t show_sampling_rate_min(struct kobject *kobj, struct attribute *attr, char *buf) { return sprintf(buf, "%u\n", min_sampling_rate); } define_one_global_ro(sampling_rate_min); /* cpufreq_ondemand Governor Tunables */ #define show_one(file_name, object) \ static ssize_t show_##file_name \ (struct kobject *kobj, struct attribute *attr, char *buf) \ { \ return sprintf(buf, "%u\n", dbs_tuners_ins.object); \ } show_one(sampling_rate, sampling_rate); show_one(io_is_busy, io_is_busy); show_one(up_threshold, up_threshold); show_one(up_threshold_multi_core, up_threshold_multi_core); show_one(down_differential, down_differential); show_one(sampling_down_factor, sampling_down_factor); show_one(ignore_nice_load, ignore_nice); show_one(optimal_freq, optimal_freq); show_one(up_threshold_any_cpu_load, up_threshold_any_cpu_load); show_one(sync_freq, sync_freq); static ssize_t show_powersave_bias (struct kobject *kobj, struct attribute *attr, char *buf) { return snprintf(buf, PAGE_SIZE, "%d\n", dbs_tuners_ins.powersave_bias); } /** * update_sampling_rate - update sampling rate effective immediately if needed. * @new_rate: new sampling rate * * If new rate is smaller than the old, simply updaing * dbs_tuners_int.sampling_rate might not be appropriate. For example, * if the original sampling_rate was 1 second and the requested new sampling * rate is 10 ms because the user needs immediate reaction from ondemand * governor, but not sure if higher frequency will be required or not, * then, the governor may change the sampling rate too late; up to 1 second * later. Thus, if we are reducing the sampling rate, we need to make the * new value effective immediately. */ static void update_sampling_rate(unsigned int new_rate) { int cpu; dbs_tuners_ins.sampling_rate = new_rate = max(new_rate, min_sampling_rate); for_each_online_cpu(cpu) { struct cpufreq_policy *policy; struct cpu_dbs_info_s *dbs_info; unsigned long next_sampling, appointed_at; policy = cpufreq_cpu_get(cpu); if (!policy) continue; dbs_info = &per_cpu(od_cpu_dbs_info, policy->cpu); cpufreq_cpu_put(policy); mutex_lock(&dbs_info->timer_mutex); if (!delayed_work_pending(&dbs_info->work)) { mutex_unlock(&dbs_info->timer_mutex); continue; } next_sampling = jiffies + usecs_to_jiffies(new_rate); appointed_at = dbs_info->work.timer.expires; if (time_before(next_sampling, appointed_at)) { mutex_unlock(&dbs_info->timer_mutex); cancel_delayed_work_sync(&dbs_info->work); mutex_lock(&dbs_info->timer_mutex); queue_delayed_work_on(dbs_info->cpu, dbs_wq, &dbs_info->work, usecs_to_jiffies(new_rate)); } mutex_unlock(&dbs_info->timer_mutex); } } static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1) return -EINVAL; update_sampling_rate(input); return count; } static ssize_t store_sync_freq(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1) return -EINVAL; dbs_tuners_ins.sync_freq = input; return count; } static ssize_t store_io_is_busy(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1) return -EINVAL; dbs_tuners_ins.io_is_busy = !!input; return count; } static ssize_t store_optimal_freq(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1) return -EINVAL; dbs_tuners_ins.optimal_freq = input; return count; } static ssize_t store_up_threshold(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || input < MIN_FREQUENCY_UP_THRESHOLD) { return -EINVAL; } dbs_tuners_ins.up_threshold = input; return count; } static ssize_t store_up_threshold_multi_core(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || input < MIN_FREQUENCY_UP_THRESHOLD) { return -EINVAL; } dbs_tuners_ins.up_threshold_multi_core = input; return count; } static ssize_t store_up_threshold_any_cpu_load(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD || input < MIN_FREQUENCY_UP_THRESHOLD) { return -EINVAL; } dbs_tuners_ins.up_threshold_any_cpu_load = input; return count; } static ssize_t store_down_differential(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1 || input >= dbs_tuners_ins.up_threshold || input < MIN_FREQUENCY_DOWN_DIFFERENTIAL) { return -EINVAL; } dbs_tuners_ins.down_differential = input; return count; } static ssize_t store_sampling_down_factor(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input, j; int ret; ret = sscanf(buf, "%u", &input); if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) return -EINVAL; dbs_tuners_ins.sampling_down_factor = input; /* Reset down sampling multiplier in case it was active */ for_each_online_cpu(j) { struct cpu_dbs_info_s *dbs_info; dbs_info = &per_cpu(od_cpu_dbs_info, j); dbs_info->rate_mult = 1; } return count; } static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b, const char *buf, size_t count) { unsigned int input; int ret; unsigned int j; ret = sscanf(buf, "%u", &input); if (ret != 1) return -EINVAL; if (input > 1) input = 1; if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */ return count; } dbs_tuners_ins.ignore_nice = input; /* we need to re-evaluate prev_cpu_idle */ for_each_online_cpu(j) { struct cpu_dbs_info_s *dbs_info; dbs_info = &per_cpu(od_cpu_dbs_info, j); dbs_info->prev_cpu_idle = get_cpu_idle_time(j, &dbs_info->prev_cpu_wall); if (dbs_tuners_ins.ignore_nice) dbs_info->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; } return count; } static ssize_t store_powersave_bias(struct kobject *a, struct attribute *b, const char *buf, size_t count) { int input = 0; int bypass = 0; int ret, cpu, reenable_timer, j; struct cpu_dbs_info_s *dbs_info; struct cpumask cpus_timer_done; cpumask_clear(&cpus_timer_done); ret = sscanf(buf, "%d", &input); if (ret != 1) return -EINVAL; if (input >= POWERSAVE_BIAS_MAXLEVEL) { input = POWERSAVE_BIAS_MAXLEVEL; bypass = 1; } else if (input <= POWERSAVE_BIAS_MINLEVEL) { input = POWERSAVE_BIAS_MINLEVEL; bypass = 1; } if (input == dbs_tuners_ins.powersave_bias) { /* no change */ return count; } reenable_timer = ((dbs_tuners_ins.powersave_bias == POWERSAVE_BIAS_MAXLEVEL) || (dbs_tuners_ins.powersave_bias == POWERSAVE_BIAS_MINLEVEL)); dbs_tuners_ins.powersave_bias = input; mutex_lock(&dbs_mutex); get_online_cpus(); if (!bypass) { if (reenable_timer) { /* reinstate dbs timer */ for_each_online_cpu(cpu) { if (lock_policy_rwsem_write(cpu) < 0) continue; dbs_info = &per_cpu(od_cpu_dbs_info, cpu); for_each_cpu(j, &cpus_timer_done) { if (!dbs_info->cur_policy) { pr_err("Dbs policy is NULL\n"); goto skip_this_cpu; } if (cpumask_test_cpu(j, dbs_info-> cur_policy->cpus)) goto skip_this_cpu; } cpumask_set_cpu(cpu, &cpus_timer_done); if (dbs_info->cur_policy) { /* restart dbs timer */ dbs_timer_init(dbs_info); } skip_this_cpu: unlock_policy_rwsem_write(cpu); } } ondemand_powersave_bias_init(); } else { /* running at maximum or minimum frequencies; cancel dbs timer as periodic load sampling is not necessary */ for_each_online_cpu(cpu) { if (lock_policy_rwsem_write(cpu) < 0) continue; dbs_info = &per_cpu(od_cpu_dbs_info, cpu); for_each_cpu(j, &cpus_timer_done) { if (!dbs_info->cur_policy) { pr_err("Dbs policy is NULL\n"); goto skip_this_cpu_bypass; } if (cpumask_test_cpu(j, dbs_info-> cur_policy->cpus)) goto skip_this_cpu_bypass; } cpumask_set_cpu(cpu, &cpus_timer_done); if (dbs_info->cur_policy) { /* cpu using ondemand, cancel dbs timer */ mutex_lock(&dbs_info->timer_mutex); dbs_timer_exit(dbs_info); ondemand_powersave_bias_setspeed( dbs_info->cur_policy, NULL, input); mutex_unlock(&dbs_info->timer_mutex); } skip_this_cpu_bypass: unlock_policy_rwsem_write(cpu); } } put_online_cpus(); mutex_unlock(&dbs_mutex); return count; } define_one_global_rw(sampling_rate); define_one_global_rw(io_is_busy); define_one_global_rw(up_threshold); define_one_global_rw(down_differential); define_one_global_rw(sampling_down_factor); define_one_global_rw(ignore_nice_load); define_one_global_rw(powersave_bias); define_one_global_rw(up_threshold_multi_core); define_one_global_rw(optimal_freq); define_one_global_rw(up_threshold_any_cpu_load); define_one_global_rw(sync_freq); static struct attribute *dbs_attributes[] = { &sampling_rate_min.attr, &sampling_rate.attr, &up_threshold.attr, &down_differential.attr, &sampling_down_factor.attr, &ignore_nice_load.attr, &powersave_bias.attr, &io_is_busy.attr, &up_threshold_multi_core.attr, &optimal_freq.attr, &up_threshold_any_cpu_load.attr, &sync_freq.attr, NULL }; static struct attribute_group dbs_attr_group = { .attrs = dbs_attributes, .name = "ondemand", }; /************************** sysfs end ************************/ static void dbs_freq_increase(struct cpufreq_policy *p, unsigned int freq) { if (dbs_tuners_ins.powersave_bias) freq = powersave_bias_target(p, freq, CPUFREQ_RELATION_H); else if (p->cur == p->max) return; __cpufreq_driver_target(p, freq, dbs_tuners_ins.powersave_bias ? CPUFREQ_RELATION_L : CPUFREQ_RELATION_H); } static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) { /* Extrapolated load of this CPU */ unsigned int load_at_max_freq = 0; unsigned int max_load_freq; /* Current load across this CPU */ unsigned int cur_load = 0; unsigned int max_load_other_cpu = 0; struct cpufreq_policy *policy; unsigned int j; this_dbs_info->freq_lo = 0; policy = this_dbs_info->cur_policy; /* * Every sampling_rate, we check, if current idle time is less * than 20% (default), then we try to increase frequency * Every sampling_rate, we look for a the lowest * frequency which can sustain the load while keeping idle time over * 30%. If such a frequency exist, we try to decrease to this frequency. * * Any frequency increase takes it to the maximum frequency. * Frequency reduction happens at minimum steps of * 5% (default) of current frequency */ /* Get Absolute Load - in terms of freq */ max_load_freq = 0; for_each_cpu(j, policy->cpus) { struct cpu_dbs_info_s *j_dbs_info; cputime64_t cur_wall_time, cur_idle_time, cur_iowait_time; unsigned int idle_time, wall_time, iowait_time; unsigned int load_freq; int freq_avg; j_dbs_info = &per_cpu(od_cpu_dbs_info, j); cur_idle_time = get_cpu_idle_time(j, &cur_wall_time); cur_iowait_time = get_cpu_iowait_time(j, &cur_wall_time); wall_time = (unsigned int) (cur_wall_time - j_dbs_info->prev_cpu_wall); j_dbs_info->prev_cpu_wall = cur_wall_time; idle_time = (unsigned int) (cur_idle_time - j_dbs_info->prev_cpu_idle); j_dbs_info->prev_cpu_idle = cur_idle_time; iowait_time = (unsigned int) (cur_iowait_time - j_dbs_info->prev_cpu_iowait); j_dbs_info->prev_cpu_iowait = cur_iowait_time; if (dbs_tuners_ins.ignore_nice) { u64 cur_nice; unsigned long cur_nice_jiffies; cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] - j_dbs_info->prev_cpu_nice; /* * Assumption: nice time between sampling periods will * be less than 2^32 jiffies for 32 bit sys */ cur_nice_jiffies = (unsigned long) cputime64_to_jiffies64(cur_nice); j_dbs_info->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; idle_time += jiffies_to_usecs(cur_nice_jiffies); } /* * For the purpose of ondemand, waiting for disk IO is an * indication that you're performance critical, and not that * the system is actually idle. So subtract the iowait time * from the cpu idle time. */ if (dbs_tuners_ins.io_is_busy && idle_time >= iowait_time) idle_time -= iowait_time; if (unlikely(!wall_time || wall_time < idle_time)) continue; cur_load = 100 * (wall_time - idle_time) / wall_time; j_dbs_info->max_load = max(cur_load, j_dbs_info->prev_load); j_dbs_info->prev_load = cur_load; freq_avg = __cpufreq_driver_getavg(policy, j); if (freq_avg <= 0) freq_avg = policy->cur; load_freq = cur_load * freq_avg; if (load_freq > max_load_freq) max_load_freq = load_freq; } for_each_online_cpu(j) { struct cpu_dbs_info_s *j_dbs_info; j_dbs_info = &per_cpu(od_cpu_dbs_info, j); if (j == policy->cpu) continue; if (max_load_other_cpu < j_dbs_info->max_load) max_load_other_cpu = j_dbs_info->max_load; /* * The other cpu could be running at higher frequency * but may not have completed it's sampling_down_factor. * For that case consider other cpu is loaded so that * frequency imbalance does not occur. */ if ((j_dbs_info->cur_policy != NULL) && (j_dbs_info->cur_policy->cur == j_dbs_info->cur_policy->max)) { if (policy->cur >= dbs_tuners_ins.optimal_freq) max_load_other_cpu = dbs_tuners_ins.up_threshold_any_cpu_load; } } /* calculate the scaled load across CPU */ load_at_max_freq = (cur_load * policy->cur)/policy->cpuinfo.max_freq; cpufreq_notify_utilization(policy, load_at_max_freq); /* Check for frequency increase */ if (max_load_freq > dbs_tuners_ins.up_threshold * policy->cur) { /* If switching to max speed, apply sampling_down_factor */ if (policy->cur < policy->max) this_dbs_info->rate_mult = dbs_tuners_ins.sampling_down_factor; dbs_freq_increase(policy, policy->max); return; } if (num_online_cpus() > 1) { if (max_load_other_cpu > dbs_tuners_ins.up_threshold_any_cpu_load) { if (policy->cur < dbs_tuners_ins.sync_freq) dbs_freq_increase(policy, dbs_tuners_ins.sync_freq); return; } if (max_load_freq > dbs_tuners_ins.up_threshold_multi_core * policy->cur) { if (policy->cur < dbs_tuners_ins.optimal_freq) dbs_freq_increase(policy, dbs_tuners_ins.optimal_freq); return; } } /* Check for frequency decrease */ /* if we cannot reduce the frequency anymore, break out early */ if (policy->cur == policy->min) return; /* * The optimal frequency is the frequency that is the lowest that * can support the current CPU usage without triggering the up * policy. To be safe, we focus 10 points under the threshold. */ if (max_load_freq < (dbs_tuners_ins.up_threshold - dbs_tuners_ins.down_differential) * policy->cur) { unsigned int freq_next; freq_next = max_load_freq / (dbs_tuners_ins.up_threshold - dbs_tuners_ins.down_differential); /* No longer fully busy, reset rate_mult */ this_dbs_info->rate_mult = 1; if (freq_next < policy->min) freq_next = policy->min; if (num_online_cpus() > 1) { if (max_load_other_cpu > (dbs_tuners_ins.up_threshold_multi_core - dbs_tuners_ins.down_differential) && freq_next < dbs_tuners_ins.sync_freq) freq_next = dbs_tuners_ins.sync_freq; if (max_load_freq > ((dbs_tuners_ins.up_threshold_multi_core - dbs_tuners_ins.down_differential_multi_core) * policy->cur) && freq_next < dbs_tuners_ins.optimal_freq) freq_next = dbs_tuners_ins.optimal_freq; } if (!dbs_tuners_ins.powersave_bias) { __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L); } else { int freq = powersave_bias_target(policy, freq_next, CPUFREQ_RELATION_L); __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L); } } } static void do_dbs_timer(struct work_struct *work) { struct cpu_dbs_info_s *dbs_info = container_of(work, struct cpu_dbs_info_s, work.work); unsigned int cpu = dbs_info->cpu; int sample_type = dbs_info->sample_type; int delay; mutex_lock(&dbs_info->timer_mutex); /* Common NORMAL_SAMPLE setup */ dbs_info->sample_type = DBS_NORMAL_SAMPLE; if (!dbs_tuners_ins.powersave_bias || sample_type == DBS_NORMAL_SAMPLE) { dbs_check_cpu(dbs_info); if (dbs_info->freq_lo) { /* Setup timer for SUB_SAMPLE */ dbs_info->sample_type = DBS_SUB_SAMPLE; delay = dbs_info->freq_hi_jiffies; } else { /* We want all CPUs to do sampling nearly on * same jiffy */ delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate * dbs_info->rate_mult); if (num_online_cpus() > 1) delay -= jiffies % delay; } } else { __cpufreq_driver_target(dbs_info->cur_policy, dbs_info->freq_lo, CPUFREQ_RELATION_H); delay = dbs_info->freq_lo_jiffies; } queue_delayed_work_on(cpu, dbs_wq, &dbs_info->work, delay); mutex_unlock(&dbs_info->timer_mutex); } static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info) { /* We want all CPUs to do sampling nearly on same jiffy */ int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); if (num_online_cpus() > 1) delay -= jiffies % delay; dbs_info->sample_type = DBS_NORMAL_SAMPLE; INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer); queue_delayed_work_on(dbs_info->cpu, dbs_wq, &dbs_info->work, delay); } static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info) { cancel_delayed_work_sync(&dbs_info->work); } /* * Not all CPUs want IO time to be accounted as busy; this dependson how * efficient idling at a higher frequency/voltage is. * Pavel Machek says this is not so for various generations of AMD and old * Intel systems. * Mike Chan (androidlcom) calis this is also not true for ARM. * Because of this, whitelist specific known (series) of CPUs by default, and * leave all others up to the user. */ static int should_io_be_busy(void) { #if defined(CONFIG_X86) /* * For Intel, Core 2 (model 15) andl later have an efficient idle. */ if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model >= 15) return 1; #endif return 0; } static void dbs_refresh_callback(struct work_struct *work) { struct cpufreq_policy *policy; struct cpu_dbs_info_s *this_dbs_info; struct dbs_work_struct *dbs_work; unsigned int cpu; dbs_work = container_of(work, struct dbs_work_struct, work); cpu = dbs_work->cpu; get_online_cpus(); if (lock_policy_rwsem_write(cpu) < 0) goto bail_acq_sema_failed; this_dbs_info = &per_cpu(od_cpu_dbs_info, cpu); policy = this_dbs_info->cur_policy; if (!policy) { /* CPU not using ondemand governor */ goto bail_incorrect_governor; } if (policy->cur < policy->max) { /* * Arch specific cpufreq driver may fail. * Don't update governor frequency upon failure. */ if (__cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_L) >= 0) policy->cur = policy->max; this_dbs_info->prev_cpu_idle = get_cpu_idle_time(cpu, &this_dbs_info->prev_cpu_wall); } bail_incorrect_governor: unlock_policy_rwsem_write(cpu); bail_acq_sema_failed: put_online_cpus(); return; } static int dbs_migration_notify(struct notifier_block *nb, unsigned long target_cpu, void *arg) { struct dbs_sync_work_struct *sync_work = &per_cpu(dbs_sync_work, target_cpu); sync_work->src_cpu = (unsigned int)arg; queue_work_on(target_cpu, dbs_wq, &per_cpu(dbs_sync_work, target_cpu).work); return NOTIFY_OK; } static struct notifier_block dbs_migration_nb = { .notifier_call = dbs_migration_notify, }; void dbs_synchronize(struct work_struct *work) { struct cpufreq_policy *policy; struct cpu_dbs_info_s *this_dbs_info, *src_dbs_info; struct dbs_sync_work_struct *dbs_work; unsigned int cpu, src_cpu; unsigned int src_freq, src_max_load; int delay; dbs_work = container_of(work, struct dbs_sync_work_struct, work); cpu = dbs_work->targ_cpu; src_cpu = dbs_work->src_cpu; get_online_cpus(); /* Getting source cpu info */ src_dbs_info = &per_cpu(od_cpu_dbs_info, src_cpu); if (src_dbs_info != NULL && src_dbs_info->cur_policy != NULL) { src_freq = src_dbs_info->cur_policy->cur; src_max_load = src_dbs_info->max_load; } else { src_freq = dbs_tuners_ins.sync_freq; src_max_load = 0; } if (lock_policy_rwsem_write(cpu) < 0) goto bail_acq_sema_failed; this_dbs_info = &per_cpu(od_cpu_dbs_info, cpu); policy = this_dbs_info->cur_policy; if (!policy) { /* CPU not using ondemand governor */ goto bail_incorrect_governor; } delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); if (policy->cur < src_freq) { /* Cancelling the next ondemand sample */ cancel_delayed_work_sync(&this_dbs_info->work); /* * Arch specific cpufreq driver may fail. * Don't update governor frequency upon failure. */ if (__cpufreq_driver_target(policy, src_freq, CPUFREQ_RELATION_L) >= 0) { policy->cur = src_freq; if (src_max_load > this_dbs_info->max_load) { this_dbs_info->max_load = src_max_load; this_dbs_info->prev_load = src_max_load; } } /* Rescheduling the next ondemand sample */ mutex_lock(&this_dbs_info->timer_mutex); schedule_delayed_work_on(cpu, &this_dbs_info->work, delay); mutex_unlock(&this_dbs_info->timer_mutex); } bail_incorrect_governor: unlock_policy_rwsem_write(cpu); bail_acq_sema_failed: put_online_cpus(); return; } static void dbs_input_event(struct input_handle *handle, unsigned int type, unsigned int code, int value) { int i; if ((dbs_tuners_ins.powersave_bias == POWERSAVE_BIAS_MAXLEVEL) || (dbs_tuners_ins.powersave_bias == POWERSAVE_BIAS_MINLEVEL)) { /* nothing to do */ return; } for_each_online_cpu(i) queue_work_on(i, dbs_wq, &per_cpu(dbs_refresh_work, i).work); } static int dbs_input_connect(struct input_handler *handler, struct input_dev *dev, const struct input_device_id *id) { struct input_handle *handle; int error; handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL); if (!handle) return -ENOMEM; handle->dev = dev; handle->handler = handler; handle->name = "cpufreq"; error = input_register_handle(handle); if (error) goto err2; error = input_open_device(handle); if (error) goto err1; return 0; err1: input_unregister_handle(handle); err2: kfree(handle); return error; } static void dbs_input_disconnect(struct input_handle *handle) { input_close_device(handle); input_unregister_handle(handle); kfree(handle); } static const struct input_device_id dbs_ids[] = { { .driver_info = 1 }, { }, }; static struct input_handler dbs_input_handler = { .event = dbs_input_event, .connect = dbs_input_connect, .disconnect = dbs_input_disconnect, .name = "cpufreq_ond", .id_table = dbs_ids, }; static int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event) { unsigned int cpu = policy->cpu; struct cpu_dbs_info_s *this_dbs_info; unsigned int j; int rc; this_dbs_info = &per_cpu(od_cpu_dbs_info, cpu); switch (event) { case CPUFREQ_GOV_START: if ((!cpu_online(cpu)) || (!policy->cur)) return -EINVAL; mutex_lock(&dbs_mutex); dbs_enable++; for_each_cpu(j, policy->cpus) { struct cpu_dbs_info_s *j_dbs_info; j_dbs_info = &per_cpu(od_cpu_dbs_info, j); j_dbs_info->cur_policy = policy; j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j, &j_dbs_info->prev_cpu_wall); if (dbs_tuners_ins.ignore_nice) j_dbs_info->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; } this_dbs_info->cpu = cpu; this_dbs_info->rate_mult = 1; ondemand_powersave_bias_init_cpu(cpu); /* * Start the timerschedule work, when this governor * is used for first time */ if (dbs_enable == 1) { unsigned int latency; rc = sysfs_create_group(cpufreq_global_kobject, &dbs_attr_group); if (rc) { mutex_unlock(&dbs_mutex); return rc; } /* policy latency is in nS. Convert it to uS first */ latency = policy->cpuinfo.transition_latency / 1000; if (latency == 0) latency = 1; /* Bring kernel and HW constraints together */ min_sampling_rate = max(min_sampling_rate, MIN_LATENCY_MULTIPLIER * latency); dbs_tuners_ins.sampling_rate = max(min_sampling_rate, latency * LATENCY_MULTIPLIER); dbs_tuners_ins.io_is_busy = should_io_be_busy(); if (dbs_tuners_ins.optimal_freq == 0) dbs_tuners_ins.optimal_freq = policy->min; if (dbs_tuners_ins.sync_freq == 0) dbs_tuners_ins.sync_freq = policy->min; atomic_notifier_chain_register(&migration_notifier_head, &dbs_migration_nb); } if (!cpu) rc = input_register_handler(&dbs_input_handler); mutex_unlock(&dbs_mutex); if (!ondemand_powersave_bias_setspeed( this_dbs_info->cur_policy, NULL, dbs_tuners_ins.powersave_bias)) dbs_timer_init(this_dbs_info); break; case CPUFREQ_GOV_STOP: dbs_timer_exit(this_dbs_info); mutex_lock(&dbs_mutex); dbs_enable--; /* If device is being removed, policy is no longer * valid. */ this_dbs_info->cur_policy = NULL; if (!cpu) input_unregister_handler(&dbs_input_handler); if (!dbs_enable) { sysfs_remove_group(cpufreq_global_kobject, &dbs_attr_group); atomic_notifier_chain_unregister( &migration_notifier_head, &dbs_migration_nb); } mutex_unlock(&dbs_mutex); break; case CPUFREQ_GOV_LIMITS: mutex_lock(&this_dbs_info->timer_mutex); if (policy->max < this_dbs_info->cur_policy->cur) __cpufreq_driver_target(this_dbs_info->cur_policy, policy->max, CPUFREQ_RELATION_H); else if (policy->min > this_dbs_info->cur_policy->cur) __cpufreq_driver_target(this_dbs_info->cur_policy, policy->min, CPUFREQ_RELATION_L); else if (dbs_tuners_ins.powersave_bias != 0) ondemand_powersave_bias_setspeed( this_dbs_info->cur_policy, policy, dbs_tuners_ins.powersave_bias); mutex_unlock(&this_dbs_info->timer_mutex); break; } return 0; } static int __init cpufreq_gov_dbs_init(void) { u64 idle_time; unsigned int i; int cpu = get_cpu(); idle_time = get_cpu_idle_time_us(cpu, NULL); put_cpu(); if (idle_time != -1ULL) { /* Idle micro accounting is supported. Use finer thresholds */ dbs_tuners_ins.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD; dbs_tuners_ins.down_differential = MICRO_FREQUENCY_DOWN_DIFFERENTIAL; /* * In nohz/micro accounting case we set the minimum frequency * not depending on HZ, but fixed (very low). The deferred * timer might skip some samples if idle/sleeping as needed. */ min_sampling_rate = MICRO_FREQUENCY_MIN_SAMPLE_RATE; } else { /* For correct statistics, we need 10 ticks for each measure */ min_sampling_rate = MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10); } dbs_wq = alloc_workqueue("ondemand_dbs_wq", WQ_HIGHPRI, 0); if (!dbs_wq) { printk(KERN_ERR "Failed to create ondemand_dbs_wq workqueue\n"); return -EFAULT; } for_each_possible_cpu(i) { struct cpu_dbs_info_s *this_dbs_info = &per_cpu(od_cpu_dbs_info, i); struct dbs_work_struct *dbs_work = &per_cpu(dbs_refresh_work, i); struct dbs_sync_work_struct *dbs_sync = &per_cpu(dbs_sync_work, i); mutex_init(&this_dbs_info->timer_mutex); INIT_WORK(&dbs_work->work, dbs_refresh_callback); dbs_work->cpu = i; INIT_WORK(&dbs_sync->work, dbs_synchronize); dbs_sync->src_cpu = 0; dbs_sync->targ_cpu = i; } return cpufreq_register_governor(&cpufreq_gov_ondemand); } static void __exit cpufreq_gov_dbs_exit(void) { unsigned int i; cpufreq_unregister_governor(&cpufreq_gov_ondemand); for_each_possible_cpu(i) { struct cpu_dbs_info_s *this_dbs_info = &per_cpu(od_cpu_dbs_info, i); mutex_destroy(&this_dbs_info->timer_mutex); } destroy_workqueue(dbs_wq); } MODULE_AUTHOR("Venkatesh Pallipadi "); MODULE_AUTHOR("Alexey Starikovskiy "); MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for " "Low Latency Frequency Transition capable processors"); MODULE_LICENSE("GPL"); #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND fs_initcall(cpufreq_gov_dbs_init); #else module_init(cpufreq_gov_dbs_init); #endif module_exit(cpufreq_gov_dbs_exit);